The field of the invention is medical imaging, and particularly, the processing of medical images in preparation for review by a doctor.
Text is often overlaid on top of medical images prior to review by a doctor or medical technologist. The medical images are two or three-dimensional arrays of digitized data that are produced by imaging equipment such as MRI systems, x-ray systems, CT scanners, PET scanners and nuclear medicine systems. This digital data is downloaded to a workstation where textual information is added by drawing fully opaque characters on top of the displayed image. Such textual characters obliterate the underlying image on the final image. In addition, the methods currently used for saving an image with text annotation destroys the underlying image data. The pixel values for the image data are replaced with the pixel values of the text annotation. The image data can never be restored when the image is saved in this manner.
Obscuring image data with textual characters is a particular problem in several situations. Displaying many images at the same time results in very small image size and allows limited space for textual information. Typically, the amount of text allowed on multi-image displays must be drastically reduced to prevent overwriting the image. Another situation arises when a region of interest (xe2x80x9cROIxe2x80x9d) in an image is to be labeled. By definition, a region of interest is an area of importance to the reviewer. Numbering or labeling of multiple ROIs is a common practice which can lead to the obscuring of valuable clinical information underneath the ROI labels.
The above problems are exacerbated when patient information or ROI labels on an image are internationalized. Internationalization leads to longer strings of text which need to be displayed and which increase the likelihood that clinically useful image data is obscured.
The present invention enables textual information or labels to be added to medical images without obscuring the underlying image data. Instead of adding opaque text or labels over the image data, the data to be rendered over the image data is blended therewith to produce semi-transparent text or labels. The underlying image data can still be seen under the text or labels, and the image data can be fully restored if necessary by reversing the blending operation.